Numerous devices are known for forming trenches in the bed of a body of water such as a lake or sea. Often, apparatus such as chain cutters and rockwheels are used to cut the trench. Such trench-cutting apparatus cuts through the soil and rock forming the seabed (hereinafter “soil”) and tends to produce an amount of spoil in front of the trench cutting apparatus. The build up of such spoil in front of the trench cutting apparatus can cause a number of problems. For example the build up of spoil can stop or inhibit the forward motion of the trench cutting apparatus. Also, soil can be caused to flow around the trench cutting apparatus to back-fill the trench before the pipe or cable is laid in the trench. Further, the build up of the soil can cause the soil to interfere with the propulsion mechanism (for example articulated vehicle tracks) of the soil cutting apparatus.
The soils of the seabed tend not to be homogeneous and cobbles and other very hard objects are often encountered by the trench cutting apparatus. Such cobbles can interfere with the operation of the trench cutting apparatus, for example by blocking soil removal devices such as dredge pumps or eductors.
Another, problem is that soil adheres to the cutting components of the trench cutting apparatus (such as the picks of a rockwheel) and causes a blockage which may prevent use of the soil cutting apparatus.
The present invention seeks to overcome or alleviate some or all of these problems.